The invention relates to an electric-contact structure for an IC package, especially to a flexible electric-contact structure including a plurality of elastic conductors arranged on an IC package substrate or a circuit board to proceed an electric connection with good co-planarity between the IC package and the circuit board.
Since long time ago, there are two ways to dispose an integrated circuit package (abbreviated as xe2x80x9cIC packagexe2x80x9d) in a circuit board (or a main board).
One way is to directly solder the IC package firmly on the circuit board, while the other way is replaceable and capable of plugging-in and pulling-out. This kind of electric-contact IC package is usually appropriate for an IC device needed to be upgraded or renewed, or it is applied for the IC device with higher single price. When one of the circuit board or the IC device is malfunctioned or needed to be renewed, then the other element may still be kept for usage; for example, a central processing unit (abbreviated as xe2x80x9cCPUxe2x80x9d) of computer is a typical example.
Please refer to FIG. 1 and FIG. 2, which is a replaceable socket typically seen in current market. Traditionally, in order to have the objectives of both the replaceable manner and the excellent electric connection, the traditional way is to dispose a plurality of pins 111 on the IC package 11, and a socket 13 having a plurality of pin holes 131 is also disposed on the circuit board 12 for providing the IC package 11 to be inserted in. The package way of the prior IC package II has two ways, that is, the lead frame and the ball grid array (abbreviated as xe2x80x9cBGAxe2x80x9d). Recently, in order to pursue the IC device with high efficiency (i.e., high heat dissipation) and high pin count, a flip chip BGA package is usually applied. Its basically constituting elements are shown as FIG. 1. An IC chip 112 is disposed on one side surface of a substrate 113 by flip chip manner, and several solders 114 are arranged on another side surface and electrically coupled to the chip 112 through the circuit design of the substrate 113, while the non-active surface of the other side of the chip 112 is then adhered with a heat sink 115. Since pin 111 is not an extremely rigid object and easily distorted and damaged during the procedure of plugging-in and pulling-out, so it is uneasy to be connected firmly to the solders 114. Therefore, in current technique, after being molded and fixed on an interposer 116, the plural pins 111 are then welded to the solders 114.
To provide the pin 111 of the IC package 11 according to the prior arts with a capability to be inserted in and also be pulled out, all the socket 13 according to the prior arts used today includes following elements: an inserting seat 132 bonded on the circuit board and having a plurality of inserting holes 131, a gliding board 133 capable of being arranged and covered on the top plane of the inserting seat 132 with a linearly gliding manner, and a pulling long rod 134 arranged at the side surface of the inserting seat 132 for driving the gliding board 133 to proceed slightly gliding movement. Inside each of the pinholes 131 of the inserting seat 132, there is a conducting metallic piece (not shown in the figure) arranged and there are solders 135 in the bottom of the pinholes 131 for being bonded and further making an electric connection to the circuit board 12. Slightly larger openings (not shown in the figure) are arranged on the gliding board 133 in positions corresponding to the pinholes 131. By pressing down the pulling long rod 134 that is rotated to a horizontal direction to the inserting seat 132 by taking the rod axis 136 as a rotation axis, the gliding board 133 is proceeded a slightly gliding motion to tightly insert the pins 111 of the IC package 11 into the pinholes 131. When the IC package 11 is going to be pulled out, the pulling long rod 134 is rotated to a vertical position formed as ninety degrees to the inserting seat 132, such that the inserting pins 111 are loosened to take out the IC package 11.
Since the pulling long rod 134 of above socket 13 occupies too large area, so an additional space is needed for accommodating the pulling long rod 134 and the rod axis 136 thereof; such that its occupying area in the circuit board is relatively larger. Therefore, the pulling long rod 134 needs a larger range for proceeding the pivoting action, and no any other element can be arranged within the pivoting and rotating space of the pulling long rod 134. So a limitation of space application is caused and, since the arranging position of the pulling long rod 134 is different, so the biasing gravity position causes the weight of the socket 13 unable to be distributed uniformly, such that the socket 13 will be damaged during connection because of the biasing position; invisibly. Furthermore, the cost will be increased for the relative industry, and this is an urgent problem needed to be solved immediately. And, in order to promote the industrial competition ability, this problem has to be broken-through as soon as possible.
The main objective of the invention is to provide a flexible electric-contact structure for an IC package, which applies a plurality of elastic conductors for proceeding a stable electric connection through physical contact, such that the shortcoming of the prior arts, it is easy for the applied metallic pins to damage the circuit board and increase the production cost, is overcome.
The secondary objective of the invention is to provide a flexible electric-contact structure for an IC package, which applies a plurality of elastic conductors to replace the pulling long rod and pins used in the traditional socket, such that the shortcomings of the prior arts, as complicated structure, larger occupied area, biased gravity center, and large operation space, etc., are overcome.
The further objective of the invention is to provide a flexible electric-contact structure for an IC package, which applies a positioning fastener to position and secure the IC substrate and the circuit board for reaching the functions of easy operation, position, and connection.
To achieve above objectives, the flexible electric-contact structure for an IC package according to the invention may provide an electric connection between the IC package and a circuit board disposed with at least one placing-and-fixing hole, wherein the circuit board has a plurality of connection pads arranged appropriately, and flexible electric-contact structure is comprised of an IC substrate, a plurality of elastic conductors, and at least one positioning fastener.
The IC substrate has a top plane and a bottom plane, both which are corresponding to each other, and the IC substrate may electrically connect to the circuit board. On the bottom plane, there is a plurality of soldering pads arranged in corresponding to the connection pads of the circuit board respectively and, on the top plane, at least one chip is supported.
The elastic conductor is configured as an arm having a first end plane and a second end plane, wherein the first end plane is connected to one of the soldering pads of the IC substrate, and the second end plane is formed as a free end. In another preferable embodiment of the invention, the first end plane may also be connected to one of the connection pads of the circuit board, and the second end plane is formed as a free end.
Wherein, by electrically connecting the IC substrate to the circuit board, a force is applied to press the elastic conductor for proceeding an appropriate displacement motion. And the positioning fastener physically connects both the IC substrate and the placing-and-fixing hole to each other for fixing the electric-contact positions between the IC substrate and the circuit board.
In a further preferable embodiment of the flexible electric-contact structure for an IC package according to the invention, flexible electric-contact structure is comprised of a circuit board, at least one IC substrate, an interposer, and at least one positioning fastener.
The circuit board has at least one connecting pad zone, which has a plurality of connection pads aligned appropriately and, at an appropriate position outside the connecting pad zone, the circuit board is further arranged with at least one placing-and-fixing hole.
The IC substrate may electrically connect to the connecting pad zone, and the IC substrate has a top plane and a bottom plane, both which are corresponding to each other. On the bottom plane, a plurality of soldering pads are arranged in corresponding to the connection pads of the circuit board respectively and, on the top plane, at least one chip may be supported.
The interposer has a plurality of through holes corresponding to the connection pads respectively and a positioning hole corresponding to the placing-and-fixing hole, wherein inside the through hole, an elastic conductor is arranged and, by applying a force on it, the elastic conductor may proceed an appropriate displacement motion.
Wherein, by arranging the interposer between the IC substrate and the circuit board, it may provide an electric connection and apply a force pressed on the elastic conductor to proceed an appropriate displacement motion. And, a positioning fastener is passed through a positioning hole at the interposer to physically connect the IC substrate and the placing-and-fixing hole for fixing the electric connection positions between the IC substrate and the connecting pad zone.